FIGS. 20 and 21 are diagrams illustrating examples of connection topologies of a storage system.
As depicted in FIG. 20, this storage system is configured to include a RAID (redundant arrays of inexpensive disks) apparatus 501 and a server 601, for example, wherein the server 601 reads and writes data from and to a logical volume provided by the RAID apparatus 501.
The storage system depicted in FIG. 20 is configured by connecting a single server 601 to the single RAID apparatus 501. The server 601 also includes a virtual disk service hardware provider (VDS hardware provider, also known as “VDSHP”), and, using the functions of the VDSHP, the server 601 makes configuration settings for the RAID apparatus 501 and rewrites the configuration information 502 in the RAID apparatus 501.
The VDSHP is a program for supporting Microsoft® Virtual Disk Service (VDS). The VDSHP defines an application program interface in place of a VDS, thereby providing a unified interface for managing disks and RAID volumes. Note that the VDS is a storage-related interface provided by Microsoft for the Windows Server 2003™ platform.
The VDSHP allows various configuration settings, such as allocation of logical unit numbers (LUNs) and affinity settings, for the RAID apparatus 501, by means of the storage management software supported by Windows Server 2003 R2 or the like.
Assuming an example where such VDSHPs are constructed, as depicted in FIG. 21, by connecting a plurality of servers (three in the example depicted in FIG. 21) 601-1, 601-2, and 601-3 to a single RAID apparatus 501.
Note that the reference symbols 601-1 to 601-3 are used hereinafter for referring to a specific server while reference symbol 601 is used when reference is made to any of the multiple servers.
In the topology wherein the plurality of servers 601 are connected to the RAID apparatus 501, the integrity of the configuration may be compromised when the VDSHPs in the servers 601 make a configuration setting for the RAID apparatus 501 simultaneously.
One known technique for assuring the integrity of the configuration is to use a management server, wherein the management server manages all modifications made by the servers 601 to the configuration information in a centralized manner by using a configuration information database (see Japanese Laid-Open Patent Publication No. 2003-108420, for example).
This technique requires, however, a configuration information database or a management server, and accordingly, may increase the system installation and operation costs.
As an alternative, another technique has been come up with, wherein, prior to making a configuration setting for the RAID apparatus 501 in the respective servers 601, configuration information 603 stored in the VDSHP is updated (refreshed) using configuration information 502 stored in the RAID apparatus 501.
FIG. 22 is a diagram illustrating a technique for refreshing configuration information in a conventional storage system.
For example, assuming that the server 601-2 wants to make a configuration setting for the RAID apparatus 501, the server 601-2 looks up the configuration information 502 in the RAID apparatus 501, before actually performing a configuration setting operation for the RAID apparatus 501.
The server 601-2 then obtains all pieces of configuration information 502 from the RAID apparatus 501, as depicted in FIG. 22, and overwrites configuration information 603-2 with the obtained can keep its configuration information 603-2 updated. The server 601-2 then modifies and sets both the configuration information 502 in the RAID apparatus 501 and the configuration information 603-2 in the server 601-2.
However, such refreshing processing for updating the configuration information 603 in the server 601 using all pieces of the configuration information 502 stored in the RAID apparatus 501 takes some time, for example, about two minutes. Experiencing such waiting time every time a user makes a configuration setting for the server 601 may impair the efficiency of processing, as well as being bothering.